Speedometer drive shaft



Feb. 7, 1928.

A. CHAMPION SPEEDOMETER DRIVE SHAFT Filed Aug. 11. 192

l Il l l patented Feb.. 7, 1928.

uiten ALBERT HAMFION, OF FLNT, lVICHIG-AN, ASSIGNOR TO A C SPARK .PLUG GMIPANY,

` UF FLINL, MCHIGN, A COMPANY Oli ittici-JUGAR".

SPEEDMETER :DRIVE SHAFT.

Application filed August l1, 1926. Serial il'o. 128,647.

This invention relates to a driving shaft lor a measuring instrument. lt has been designed more particularly in connect-ion with the transmission mechanism .tor operating the driven member of a speedometer from a part, the speed ot whichl is to be measured.

An object ot the invention is to provide an improved driving shatt in the relation stated.

The invention is herein tully described and is illustrated in the accompanying draw ing..

ln the drawing:

lligure l is a plan view of a vehicle chassis having my invention applied thereto..

Figure 2 is a view in elevation partly in section.

Figure 3 is a longitudinal sectional detail.

Referring by reference characters to the drawing, numeral l is used to designate the vehicle chassis, 3 being applied to the transu mission housing and 5 to the iframe member ot the chassis. lUpon the instrument board 7 is a speedometer 9 of any preferred construction. The transmission housing has a tltting il to carry a shaft geared to certain of the shafts within the housing utilized in connection with the usual drive for the ve hicle. ln the ordinary arrangement a ilexible shalt contained in a flexible housing transmits the drive trom the power talreoti shalt of the transmission housing to the speedometer. rthe tleXible drive shalt or cable is subject to a twisting action which is productive ot no objectionable results as ordinarily used where the length ot the cable is not unduly great. However, on some vehicles, such as trucks, where the distance be tween the transmission housing and the in strument is considerable, there arises an ob j ection to the use ot a long flexible cable own ing to the excessive twisting` action. To overcome this objection l provide the following remedy., l rigid driving rod or shalt is introduced into the drive mechanism between the transmission housing and the speedometer. Preferably this rigid driven sha-ift will be as long as conveniently possible and its ends are connected by the usual desi-ble cable to the instrument at one end and to the power take-oil' shai't at the other end. 'lio this end at two points along the chassis trame substantially opposite the instrument and the transmission housing are` clamps i2 held by Jastenings means 13. A tubular shaft l5 is secured within these clamps by the use ot' set screws 17. Within the tubular housing and carried by bear ings i9 therein is a driving rod or shalt 21, the same being non-circular in shape at its ends, as shown at 22. 'lhe shaft 2l is substantially the same length as the tubular member 15. Externally the ends oi' the housn ing l5 are to be connected to the tlexible housing carrying the flexible drive shalt 2'?. F or the purpose of this connection the drive shalt 27 is shown as equipped with a non-circular Vopening' at its end to receive the correspondingly shaped end 22 of shaft 2l. llhe llexible housing 25 is outwardly tlared at its end to term an abutment 29 holding a threaded collar 3l, which collar engages the external threads on the tubular member 15. A connection such as described is made at each o'll the two ends of the tubular member l5. One flexible drive is connected as usual with the speedometer, as shown in Figure l. and the other connection is made with the power takeodl at the transmission housing.

By the above described arrangements the excessive twist of the driving cable is avoided in those instances where t-he measuring instrument is located at an unusually great distance from the source et power which is to operate it. The instrument is therefore more quickly responsive to speed changes.

W'hile the source of power as herein shown is the power take-oil associated with the transmission housing it will be understood that the invention may be embodied in a structure where the power is taken oil elsewhere than at the transmission housing 3 as, for example, at the rear axle, or from the front wheels. ln either of these cases it will be readily understood that use may be made ot a rigid driving shatt having its ends connected by flexible cables with the driven instrument and with the driving means. lt is also possible that under certain circumstances the rigid shaft may be dil tid

Bil

directly connected to either the driving or tatable mounted therein, a measuring indriven element in which case the invention strument, driving means therefor exible may be embodied with the use of a single driving connections between the ends of said l0 flexible connection. driving shaft and said measuring instrument 5 I claim: and driving means, respectively.

In a vehicle, a chassis frame, an elon `ated In testimony whereof I aix my si ature. member mounted thereon, a rigid sha ro- ALBERT CH ION. 

